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OHSU Researchers Study Benefits of Treatments Within Hours of Stroke

11/30/99 Portland, Ore.

Research shows both response time and method of treatment critical.

Researchers from the Oregon Stroke Center at Oregon Health Sciences University have always known that battling a stroke is a race against time. Now, two independent studies conducted through the Oregon Stroke Center Hospital Network show medical response time can dictate which treatment may offer the most promising outcome for a patient. Both studies will be printed in the Dec. 1 edition of The Journal of the American Medical Association.

The first study involves a drug known simply as t-PA, often considered the first line of defense by doctors. The drug is used to combat strokes caused by blood clots in the brain. It works to dissolve the clot, clearing the blockage. The drug has proved to improve stroke recovery if it is administered within three hours of a stroke. However, it was not known if t-PA also would work if given after three hours, until now.

Researchers used t-PA to treat more than 600 stroke patients at sites across North America, including 71 patients in Oregon. Patients were given either the drug or a placebo within three to five hours of having their stroke. In patients treated after three hours, researchers noted no benefit in terms of improved recovery when the patients were tested at three months; however, the drug did increase the chance of serious cranial bleeding. These results demonstrate that t-PA should not be used after three hours.

The second study, also to be published in the Dec. 1 issue of JAMA, offers hope for patients who are unable to get treatment within three hours of a stroke. In this situation, another form of therapy has shown promise. This treatment involves the direct application of a clot-busting drug called ProUrokinase to the blocked artery using a catheter. The procedure is called an angiogram. Once again, health centers across North America were involved in the trial, including OHSU and Portland Veterans Affairs Medical Center.

In this study, doctors were limited to treating patients with a blockage in the middle cerebral artery, which is the major artery to the brain. The treatment was offered to those who had suffered a large stroke within the previous six hours. Despite the physical limits of working with a catheter, this therapy offered doctors a longer window of opportunity for treating patients. Three months following the initial treatment, doctors witnessed an excellent recovery for 40 percent of the patients treated with ProUrokinase, compared to only 25 percent of untreated patients. However, unlike t-PA, which can be given at any hospital, this catheter treatment is only available at a few specialized stroke centers.

Wayne Clark, M.D., associate professor of neurology and director of the Oregon Stroke Center at OHSU, says both studies provide doctors with information needed to make critical decisions following a stroke. "It is hoped that the findings of these two studies will help doctors decide which type of stroke therapy is best for the patient," said Clark. "This research accompanied by the emergence of promising new treatments, should help increase the chances that stroke patients undergo a complete recovery."

The Oregon Stroke Center is recognized as a national leader in research and patient care. The center is home to a mobile stroke team available 24 hours a day to treat patients at five Portland-area hospitals in the critical early stages of a stroke. Providence St. Vincent Hospital, Providence Portland Hospital, Legacy Emanuel Hospital, Portland VA Medical Center and OHSU are partners on the stroke team.